Oliver Cowdery initially wrote “neither need ye suppose”. Somewhat later (with slightly heavier ink flow), he crossed out the ye, but then he immediately restored the ye supralinearly (again with slightly heavier ink flow). He may have been confused by the word order of “ye need not suppose”, which is found in the preceding clause (“ye need not suppose that it contains all my words”) as well as earlier in the preceding verse (“ye need not suppose that I cannot speak another”). The inverted word order of “neither need ye suppose” may have momentarily confused Oliver since in the earlier clauses there is no ye after need or immediately before suppose. In any event, the original manuscript (which is not extant here) undoubtedly read “neither need ye suppose”.
Summary: Maintain in 2 Nephi 29:10 the original (and final) reading in 𝓟 of “neither need ye suppose”.